1. Field of the Invention
The present invention relates generally to devices, systems, and methods for measuring the presence of an analyte in a medium and, more specifically, to an optical sensing apparatus and housing permitting continuous exposure to the desired medium.
2. Description of the Related Art
Sensors for Medicine and Science, Inc. (SMSI) has developed a number of very small wireless sensors for monitoring various analytes (e.g., glucose, CO2, O2, etc.) present in a body or other medium. In certain embodiments, these very small sensors are adapted to be implanted into a human or animal to measure the presence, absence, or quantity of an analyte in the blood, wherein the sensor itself detects and measures an analyte within its immediate surroundings. The wireless sensors are described more fully in, for example, U.S. Pat. Nos. 5,517,313, 6,330,464, 6,400,974, 7,135,342, and 6,940,590, which are incorporated herein by reference in their entirety.
In certain embodiments, these very small implantable sensors are powered by induction from a primary coil contained within an external reader that is configured, for example, as a wristwatch, pager or other devices, and a secondary coil printed on the circuit substrate within the sensor itself. In certain embodiments, the sensor receives power, and transmits its data, via this primary and secondary coil electromagnetic link. See, for example, U.S. Pat. No. 6,400,974, which is incorporated herein by reference in its entirety.
Although one design application is human or animal implant monitoring, there is a need for new and improved wireless sensors and methods for using wireless sensors in a range of other applications to provide continuous measurement of an analyte in a medium.